I think you have to factor in McDaddy missing a few games, putting more of an onus on Drai, and he delivered, thereby making that line look great.
I just feel like he should start on the second line with Drai as his Centre as he might transition easier into the league not having to face the top lines. Move RNH to line #1. But McD would shoulder most of the attention so he can theoretically roam free.
If you do slot him at #1, who would be the RW? Like you said it would mess up the line chemistry.
I think the chemistry on line one would remain, McDavid can play with anyone except Taylor Hall. I assume RW would remain Kass.
I think he will transition fine. Devils didnt seem worried about Jack hughes, and Alexis is an objectively better prospect.
I think he can survive on the first line with McDavid, and RNH is a steady presence on the second line with Draisaitl. I trust Yamamotos development more with two centres on his line, rather than a rookie who will be making mental mistakes. Dont really want their inexperience feeding into each other, it's not like they have Bergeron as their centre, regardless of simpler matchups. Tbh it's more Yamamotos development I worry about, the Oilers need a win in actually sticking a prospect they dont draft in the top 5. Hes only shown 20-30 good games with Draisaitl, so I dont think it's set in stone that he will automatically have a strong year next year. Much as oiler fans would like to believe.
Of course this is all make believe until we actuslly lose to chicago (which I dont think we will and I dont want to see) and we hit on 12.5% odds.